Farthest Planet from the Sun - Universe Today Universe Today Farthest Planet from the Sun Article Updated: 24 Dec , 2015 by Fraser Cain [/caption] Like many planets, Neptune’s orbit isn’t exactly circular. Instead, Neptune orbits the Sun in an elliptical orbit. At its closest point, Neptune gets within 4.45 billion km, and then orbits out to a distance of 4.55 billion km. It takes almost 165 years to complete one orbit around the Sun. It’s a shame Pluto isn’t a planet any more, because it’s really far. Pluto gets as close as 4.44 billion km. But its orbit is so elliptical that it gets out to a distance of 7.38 billion km. In fact, there are times in Pluto’s orbit when Neptune passes it. Then Neptune really is the farthest planet from the Sun, whether or not you think Pluto is a planet. What’s farthest object from the Sun? Astronomers think that the long period comets come from a region of the Solar System known as the Oort cloud.

It’s possible that this region extends out from the Sun to a distance of 50,000 astronomical units (1 AU is the distance from the Earth to the Sun). Here’s an article that lists the distances to all the planets . And here’s an article from Solar Views that talks about the Oort Cloud. We have recorded an episode of Astronomy Cast just about the Sun called The Sun, Spots and All . Order of the Planets From The Sun – Planet Closest Distance to the Sun – PlanetFacts.org The Moon Order of the Planets From The Sun The solar system is a group of celestial bodies orbiting around the dwarf star called the Sun. The main members of the solar system are eight major planets, and their satellites. Other interesting members are comets, meteors and meteorites and dwarf planets. The order of the planets from the Sun from nearest to the farthest is Mercury, Venus, earth, Mars, Jupiter, Saturn Uranus, and Neptune. 1. The nearest planet to the Sun is Mercury. Though it is very near to the Sun, it is not the hottest planet at all.

The smallest among the inner planets has actually temperature of 450 degrees Celsius during day time while it drops to a very frigid negative 170 degrees Celsius at night. It is named after the Roman messenger of the Gods as it orbits the Sun once every 88 days. 2. The second planet from the Sun is named after the Roman Goddess of Beauty, Venus. True to its name, this beautiful planet is also called the evening star. It is also the hottest planet in the solar system due to clouds of toxic gas with temperatures over 460 degrees Celsius. It rotates backward and makes one complete revolution around the Sun in 225 days. 3. The third planet from the Sun is Earth, the beautiful blue planet blessed with a diversity of living organisms of varying shapes and sizes. It is the only planet known to sustain life. It makes a complete revolution around the Sun for 365 days. It has one satellite called the Moon. 4. Mars is the fourth planet from the Sun. It is named after the Roman God of War. It is usually called the red planet. A Martian year is equivalent to 687 Earth days.

It is usually the third brightest object of the night sky after Earth’s moon and Venus. The possibility of life on Mars is still a subject of probes and studies. By the way, Mars has similar seasons as here on Earth. 5. The biggest planet, Jupiter is the fifth planet from the Sun. Although it has the greatest volume among the planets, it has the lowest density. It is separated from the inner planets by the asteroid belt where many other interesting heavenly bodies orbit around the Sun. 6. Saturn is the second of the outer planets and is the sixth in order from the Sun. Many astronomers tag it as the most beautiful planet because of its prominent rings made up of ice, dust, gas, and other particles. 7. Uranus is the third of the outer planets, the seventh in order from the Sun. This planet has a very low density and is made up of a large proportion of gas. It is also referred to as an ice giant because a decent percentage of its gases are trapped in ice form. It has faint rings. 8. Neptune is the fourth among the outer planets and the farthest planet away from the Sun. It is also made up of frozen gases like its neighboring planet Uranus.

A great percentage of these gases are methane making it appear as a blue planet. What was once recognized as the ninth solar planet, Pluto, was just recently reclassified as a dwarf planet. It was placed in this category along with Eris, Vespa, and Ceres. Awesomeninja 18hunter235 ASP: Pluto: The Farthest Planet (Usually) © 1988, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112 Pluto: The Farthest Planet (Usually) Pluto, the ninth planet in our solar system, was not discovered until 1930 and remains a very difficult world to observe because it's so far away. At an average distance of 2.7 billion miles from the Earth, Pluto is a dim speck of light in even the largest of our telescopes. It takes almost 249 years to make one swing around the Sun, in a long looping orbit that takes it above and below the path of the other planets. (See the accompanying box for more on its unusual path.) What Would It Be Like on Pluto?

While astronomers don't yet know many details about the landscape on Pluto, we do know that it's cold and dark out there. On average, Pluto is nearly 40 times as far from the Sun as we are. From that great distance, the Sun would look like a single, brilliant point of light (it would be only about 1/40th as big as the full Moon is in our sky — too small to appear as a disk.) During the day, that tiny point illuminates the ground on Pluto with only 1/1500th the intensity of sunlight we receive on Earth. (That's still far from being "dark,'' though: the Sun's light output as seen from Pluto is about 250 times the light we receive from the Moon when it's full.) As you might expect, Pluto isn't warmed much by the Sun; astronomers estimate its surface temperature to be more than 200 degrees below zero, Celsius. This is a temperature so cold that skin would be as brittle as glass — and that some materials we're familiar with as gas or Earth (such as methane) would freeze solid.

New Discoveries in the Last Decade Despite its great distance, Pluto has given up some of its secrets to careful study recently. Even though no spacecraft has investigated Pluto (and none is scheduled to), a happy circumstance is in part responsible for the accelerating pace of discoveries: Pluto is closer to us in the last two decades of the 20th century than it has been for the last 200 years (or will be for the next 200). Along with the great sensitivity and sophistication of today's astronomical instruments, this makes investigating Pluto from Earth less difficult now. In 1978, for example, a relatively large satellite was discovered around Pluto and named Charon — and during the last half of the 1 980's, a rare alignment has made it possible to study Pluto and Charon much more effectively than ever before. For a brief period once every 124 years, observers on Earth are in a position to see Charon pass directly in front of and behind Pluto in its 6.4-day orbit around the planet.

This "eclipse season'' began in 1985 and will end in 1990; there won't be another one until the 22nd century — and not until the 23rd century will one happen when Pluto is this close. By making careful measurements of the eclipses, astronomers have made great progress in understanding the sometimes strange and puzzling properties of Pluto and its satellite. Pluto is Not the Ninth Planet Ever since 1930, school children have memorized the nine planets in order: Mercury, Venus, Earth, Mars, Jupiter Saturn, Uranus, Neptune, and PIuto. But between January, 1979 and March, 1999 that order is not correct. Pluto's eccentric (ellipse-shaped) orbit has brought it inside the orbit of Neptune, making it the eighth planet for two decades. Pluto's unusual position makes "What is the ninth planet?'' a great trivia question for a while. Just in case students begin to worry that someday Pluto might collide with Neptune as the smaller planet crosses the orbit of the larger, you can reassure them.

The two orbits are tilted relative to one another by 17 degrees) in such a way that they never actually "touch.'' (Imagine two enormous, slightly elongated hula hoops, one larger than the other. If the larger one is tilted relative to the smaller one, you can imagine that the two points where the larger hoop crosses through the smaller hoop's plane can be outside the smaller hoop.) Calculations indicate that Pluto's and Neptune's orbits are never closer than 385 million kilometers to one another and that (at least for the past several million years) the two planets themselves have never been closer than two and a half billion kilometers to each other. Some Pluto History The eighth planet from the Sun, Neptune, was discovered in 1846 at precisely the position that two mathematicians one English and one French—had predicted it would be. John C . Adams and Urbain J.J. Leverrier had calculated that a new planet must be responsible for the fact that the motion of the seventh planet, Uranus, was not in accord with the laws of planetary orbits (derived from Newton's theory of gravitation).

In essence, they reasoned that some significant body, more distant than Uranus, must be adding an extra influence on its movement. Astronomer Johann Galle at the Berlin Observatory then found Neptune on the very first night he began to search! As you can imagine, this success naturally led astronomers to wonder if even more distant planets could be found in this way. Unfortunately, Neptune takes 165 years to complete its orbit around the Sun and, as the 20th century arrived, it had only moved through a small part of its orbit. This made it very difficult to calculate the degree to which it was not orbiting "properly'' and other bodies might be disturbing it. Nevertheless, a number of astronomers attempted to calculate where a ninth planet might be from possible "oddities'' in the motions of both Uranus and Neptune. The best-known predictor of a ninth planet was a wealthy Bostonian named Percival Lowell, whose advocacy of the possibility of life on Mars had brought him fame in the 1890's and 1900's. Lowell built one of the finest observatories in the country just outside Flagstaff, Arizona, in part to pursue his dreams of Martians and new planets.

Neither could be found by the lime of his death in 1916. Nevertheless, Lowell's dream was kept alive by the trustees and staff of the Lowell Observatory, and in the late 1920's Lowell's brother Lawrence (who was president of Harvard University for many years) gave $10,000 to fund a special wide-angle 13-inch telescope to make a thorough photographic search for a ninth planet. Because the large photographs typically taken by such telescopes are full of huge numbers of stars, it was clear to the astronomers at Lowell that many months and perhaps years of careful photography — and very patient inspection of the photographs — might be required to find their planet. Someone would have to sit night after night in a cold, open dome and then spend the days searching the negatives for a moving minuscule black dot among the thousands of stationary ones. It occurred to them that it would perhaps be best to train a good amateur astronomer who could dedicate himself to the task. Two telescopic photographs of Pluto (the dot at the arrow's tip) taken 24 hours apart.

By carefully checking its position against the background star pattern, you can see that it has moved a little from the first picture (left) to the second (right). (Photographs courtesy of Yerkes Observatory.) Pluto's Discovery By happy coincidence, a young farm boy from western Kansas wrote to the director of Lowell in 1928, enclosing some careful drawings of Jupiter and M ars that he had made while observing with his home-made 9-inch telescope. A few months afterwards, 22-year old Clyde Tombaugh boarded a Santa Fe train at Larned, Kansas and arrived at Flagstaff 28 hours later to begin the search for what came to be called Pluto. The typical photographic image Tombaugh used — recorded on plates of glass to have a good permanent record — might contain anywhere from 50,000 to 400,000 stars, galaxies, and asteroids. How could the faint image of a distant planet be distinguished? The trick was to take two photographs of each region of the sky several days apart. Then the pair of plates could be put side by side into a machine called a blink comparator, in which the two images are quickly alternated (blinked) in a single viewer.

If an object is in the same place on both plates (as a star wouId be), no motion will be seen as the plates are switched in the viewer. But if the object has moved in the few days that elapsed between the taking of the plates (as a planet would do), its image will "blink'' — shift back and forth against the still background of the stars. Even with this machine, it was an enormous and painstaking task to cover the parts of the sky in which planets were expected to be found. It took almost a year of searching, but on February 18, 1930, while blinking two plates of a region in the constellation Gemini, Tombaugh discovered a new planet not far from where Lowell had predicted it wouId be — although much fainter than he had suggested. After confirmation and careful study, the announcement was made on March 13th, the 149th anniversary of the discovery of Uranus and the 75th anniversary of Percival Lowell's birth. Eventually, following the suggestion of a British schoolgirl, the planet was named Pluto, after the Roman god of the underworld.

(Another point in favor of the name was that the first two letters were Percival Lowell's initials!) Pluto's Moon In 1978, astronomer James Christy was examining some photographs of Pluto taken with the U.S. Naval Observatory's telescope near Flagstaff — not far from Lowell Observatory. He noticed that the image was slightly distorted — it bulged out on one side as if Pluto had something next to it. After looking more carefully at photographs that had been taken in the past, Chrisly was able to show that Pluto had a satellite orbiting it at a distance of about 17,000 kilometers. He suggested the name Charon — after the boatman who ferried the dead into the realm of Pluto in mythology — and the name was made official by the International Astronomical Union in 1985. Charon orbits around Pluto in about 6.4 Earth days, which is exactly the time it takes Pluto to spin around once on its axis. In other words, the day and month on Pluto are the same length, a situation which only holds for Pluto and Charon out of all the planets and satellites in the solar system.

However, there are many artificial satellites around Earth for which this is also the case. Called "geosynchronous'' satellites, these orbit above our planet's equator at exactly the same rate as the Earth spins — so they seem to "hover'' (22,000 miles up) over the same place on Earth all the time. Most satellites which are used to relay television signals are of this variety, so that receivers on the ground ("satellite dishes'') can just be pointed at one direction in the sky and then left alone — the geosynchronous satellite will always appear to be in just about the same place in the sky. Pluto's moon Charon, then, can be thought of as a "Pluto-synchronous'' satellite — it would always be in the same place in the sky if you were on Pluto. It would be an eerie sight, too. Even though Charon is only about a quarter the size of our own Moon, it's so close to Pluto that it would look bloated to Earth-trained eyes: it would be eight times as wide as the full Moon appears on Earth, covering 64 times as much sky.

(It would be dim, though — remember that it is reflected sunlight that makes a moon shine, and sunlight out there at Pluto and Charon is very dim.) Hanging in the same place in the sky, day and night, it would go through its full cycle of phases from one Pluto day to the next (that is, every 6.4 Earth days) . During the "eclipse season'' there would be an eclipse of the Sun for a while every day (while Charon blocks the Sun from view) and an eclipse of the moon at night (while Charon moves through Pluto's shadow). The Latest Discoveries Pluto is so far away and difficult to see that not very much could be pinned down about its detailed characteristics until the "eclipse season'' began. Since no spacecraft is scheduled to visit Pluto, this is our one and only chance for the foreseeable future to understand what happens in the distant realm that (usually) marks the edge of our planetary system. Astronomers at various observatories have been studying the Pluto-Charon system intensely and a preliminary report on their work was given at a recent meeting of the American Astronomical Society in Austin, Texas.

The diameters of the two bodies could be measured accurately for the first time during the eclipses. Pluto turns out to be only about 2300 kilometers across (1400 miles) — clearly making it the smallest planet in the solar system. In fact, seven moons (including the Earth's) are larger than Pluto. Charon is about 1300 kilometers wide (or roughly 800 miles). While much smaller than our Moon's 3500 kilometer diameter, this is so large compared to Pluto — more than half as big — that some astronomers are now speaking of the Pluto-Charon system as a "double planet.'' The next closest thing to a double planet is our own Earth-Moon system, but our satellite is only about one-fourth the diameter of our planet. (It must be noted that these measurements of Pluto's and Charon's diameters are not — and cannot yet be — precise. It would not be surprising if the numbers given here wind up being "wrong'' by a hundred kilometers or so after all the measurements from the eclipse season are evaluated.) By measuring Pluto's pull on Charon as the satellite moves around the planet, astronomers can estimate the mass of Pluto.

(Current best estimates are that Pluto's mass is about 3/1000th that of the Earth.) From knowing the mass and the diameter, Pluto's average density (mass per unit volume) can be calculated, giving us a due to what this remote world is made of. On a scale where water has a density of 1.0 and the Earth about 5.5, Pluto comes in at about 2. This means it cannot be made just of ice, but must also contain denser (rocky) material. Knowing Pluto's approximate mass and diameter also allows us to estimate the strength of Pluto's gravity at its surface — it turns out to be only a percent or two of Earth's! A 100-pound Earth student would weigh only a pound or two on Pluto. The faint reflected sunlight we pick up from the two bodies shows that Pluto has a surface with a considerable amount of frozen methane (sometimes called "swamp gas'' on Earth), while Charon's surface seems to be mostly water ice. The very existence of methane ice is an indication of how cold things must be out there — methane does not become a solid until the temperature drops to nearly 200 degrees below zero Celsius.

With its small size, relatively large moon, and weird orbit, Pluto certainly seems like an oddball world compared to the other planets in the outer solar system. One explanation that is sometimes offered for its unusual properties is that it was once a moon of Neptune that escaped long ago and took up an independent orbit after a while. However, even though Pluto's orbit sometimes carries it closer to the Sun than Neptune is, today their orbits never actually cross. This is because Pluto's orbit is in fact outside Neptune's at the places where their planes cross. (On the other hand, planets' orbits do change somewhat over very long periods of time, so it is possible that Pluto's and Neptune's orbital paths did actually cross long ago.) Furthermore, scientists are not sure what might have caused such a moon to escape and how an escaped moon could have a satellite of its own; so Pluto's origin must remain one of the solar system's unsolved mysteries for now. Resource Corner Hoyt, W. Planets X and Pluto. 1980, U. of Arizona Press. Tombaugh, C. & Moore, P. Out of the Darkness: The Planet Pluto. 1980, Stackpole Books. Articles About Pluto: Beatty, J.

K. "Pluto and Charon: The Dance Goes On'' in Sky & Telescope, Sep. 1987, p. 248. Croswell, K. "Pluto: The Enigma at the Edge of the Solar System'' in Astronomy, July 1986, p. 6. Eberhart, J. "Pluto: Limits on its Atmosphere, Ice on its Moon'' in Science News, Sep. 26, 1987, p. 207. (1-page news article.) Eicher, D. "How to Hunt Down Pluto'' in Astronomy, Apr. 1 9B4, p. 35. Harrington, R. & B. "The Discovery of Pluto's Moon'' in Mercury, Jan/Feb 1979, p. 1. Moore, P. "The Naming of Pluto'' in Sky & Telescope, Nov. 1984, p. 400. Mulholland, D. "The Ice Planet'' in Science 82, Dec. 1982, p. 64. Tombaugh, C. "The Discovery of Pluto'' in Mercury, May/June 1986, p.

66 and Jul/Aug 1986, p. 98. (The full story by the discoverer.) << previous page | 1 | 2 | 3 | 4 | next page >> Is Pluto or Neptune farthest from the Sun? Is Pluto or Neptune farthest from the Sun? Answer: Pluto is usually farthest from the Sun. However, its orbit "crosses" inside of Neptune's orbit for 20 years out of every 248 years. Pluto last crossed inside Neptune's orbit on February 7, 1979, and temporarily became the 8th planet from the Sun. Pluto will cross back over Neptune's orbit again on February 11, 1999 to resume its place as the 9th planet from the Sun for the next 228 years. So will Pluto and Neptune ever collide? No! You can see this in the image below, which shows a view as seen from the side as the planets orbit around the Sun. Most planets only make small excursions in the vertical and radial directions, but Pluto is an exception.

Pluto at times will move closer to the Sun than Neptune, but it is always well above the orbit of Neptune when this happens. The orbits never actually cross the same point in space. You can read more about the orbital patterns of Pluto at: Order Of the Planets From The Sun - Universe Today Universe Today Order Of the Planets From The Sun Article Updated: 31 Jan , 2016 by Nancy Atkinson First the quick facts: Our Solar System has eight “official” planets which orbit the Sun. Here are the planets listed in order of their distance from the Sun: Mercury , Venus , Earth , Mars , Jupiter , Saturn , Uranus , and Neptune . An easy mnemonic for remembering the order is “My Very Educated Mother Just Served Us Noodles.” If you add in the dwarf planets, Ceres is located in the asteroid belt between Mars and Jupiter, while the remaining dwarf planets are in the outer Solar System and in order from the Sun are Pluto , Haumea , Makemake , and Eris .

There is, as yet, a bit of indecision about the Trans-Neptunian Objects known as Orcus , Quaoar , 2007 O10 , and Sedna and their inclusion in the dwarf planet category. A mnemonic for this list would be “My Very Educated Mother Could Just Serve Us Noodles, Pie, Ham, Muffins, and Eggs” (and Steak, if Sedna is included.) You can find more tricks for remembering the order of the planets at our detailed article here. Now, let’s look at a few details including the definition of a planet and a dwarf planet, as well as details about each of the planets in our Solar System. Artistic impression of the Solar System, with all known terrestrial planets, as giants, and dwarf planets. Credit: NASA What is a planet? In 2006, the International Astronomical Union (IAU) decided on the definition of a planet. The definition states that in our Solar System, a planet is a celestial body which: is in orbit around the Sun, has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), has “cleared the neighborhood” around its orbit. is not a moon.

This means that Pluto, which was considered to be the farthest planet since its discovery in 1930, now is classified as a dwarf planet. The change in the definition came after the discovery three bodies that were all similar to Pluto in terms of size and orbit, (Quaoar in 2002, Sedna in 2003, and Eris in 2005). With advances in equipment and techniques, astronomers knew that more objects like Pluto would very likely be discovered, and so the number of planets in our Solar System would start growing quickly. It soon became clear that either they all had to be called planets or Pluto and bodies like it would have to be reclassified. With much controversy then and since, Pluto was reclassified as a dwarf planet in 2006. This also reclassified the asteroid Ceres as a dwarf planet, too, and so the first five recognized dwarf planets are Ceres, Pluto, Eris, Makemake and Haumea. Scientists believe there may be dozens more dwarf planets awaiting discovery.

Later, in 2008, the IAU announced the subcategory of dwarf planets with trans-Neptunian orbits would be known as “plutoids.” Said the IAU, “Plutoids are celestial bodies in orbit around the Sun at a distance greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighborhood around their orbit.” This subcategory includes Ceres, Pluto, Haumea, Makemake, and Eris. The Planets in our Solar System: Having covered the basics of definition and classification, let’s get talking about those celestial bodies in our Solar System that are still classified as planets (sorry Pluto!). Here is a brief look at the eight planets in our Solar System. Included are quick facts and links so you can find out more about each planet. Mercury: Mercury is the closest planet to our Sun, at just 58 million km (36 million miles) or 0.39 Astronomical Unit (AU) out.

But despite its reputation for being sun-baked and molten, it is not the hottest planet in our Solar System (scroll down to find out who that dubious honor goes go!) Mercury, as imaged by the MESSENGER spacecraft, revealing parts of the never seen by human eyes. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington Mercury is also the smallest planet in our Solar System, and is also smaller than its largest moon (Ganymede, which orbits Jupiter). And being equivalent in size to 0.38 Earths, it is just slightly larger than the Earth’s own Moon. But this may have something to do with its incredible density, being composed primarily of rock and iron ore. Here are the planetary facts: Diameter: 4,879 km (3,032 miles) Mass: 3.3011 x 1023 kg (0.055 Earths) Length of Year (Orbit): 87.97 Earth days Length of Day: 59 Earth days. Mercury is a rocky planet, one of the four “terrestrial planets” in our Solar System.

Mercury has a solid, cratered surface, and looks much like Earth’s moon. If you weigh 45 kg (100 pounds) on Earth, you would weigh 17 kg (38 pounds) on Mercury. Mercury does not have any moons. Temperatures on Mercury range between -173 to 427 degrees Celcius (-279 to 801 degrees Fahrenheit) Just two spacecraft have visited Mercury: Mariner 10 in 1974-75 and MESSENGER, which flew past Mercury three times before going into orbit around Mercury in 2011 and ended its mission by impacting the surface of Mercury on April 30, 2015. MESSENGER has changed our understanding of this planet, and scientists are still studying the data. Find more details about Mercury at this article on Universe Today, and this page from NASA. Venus: Venus is the second closest planet to our Sun, orbiting at an average distance of 108 million km (67 million miles) or 0.72 AU. Venus is often called Earth’s “sister planet,” as it is just a little smaller than Earth.

Venus is 81.5% as massive as Earth, and has 90% of its surface area and 86.6% of its volume. The surface gravity, which is 8.87 m/s², is equivalent to 0.904 g – roughly 90% of the Earth standard. A radar view of Venus taken by the Magellan spacecraft, with some gaps filled in by the Pioneer Venus orbiter. Credit: NASA/JPL And due to its thick atmosphere and proximity to the Sun, it is the Solar Systems hottest planet, with temperatures reaching up to a scorching 735 K (462 °C). To put that in perspective, that’s over four and a half times the amount of heat needed to evaporate water, and about twice as much needed to turn tin into molten metal (231.9 °C)!

Diameter: 7,521 miles (12,104 km) Mass: 4.867 x 1024 kg (0.815 Earth mass) Length of Year (Orbit): 225 days Length of day: 243 Earth days Surface temperature: 462 degrees C (864 degrees F) Venus’ thick and toxic atmosphere is made up mostly of carbon dioxide (CO2) and nitrogen (N2), with clouds of sulfuric acid (H2SO4) droplets. Venus has no moons. Venus spins backwards (retrograde rotation), compared to the other planets. This means that the sun rises in the west and sets in the east on Venus. If you weigh 45 kg (100 pounds) on Earth, you would weigh 41 kg (91 pounds) on Venus. Venus is also known and the “morning star” or “evening star” because it is often brighter than any other object in the sky and is usually seen either at dawn or at dusk. Since it is so bright, it has often been mistaken for a UFO! More than 40 spacecraft have explored Venus.

The Magellan mission in the early 1990s mapped 98 percent of the planet’s surface. Find out more about all the missions here. Find out more about Venus on this article from Universe Today , and this page from NASA. Earth: Our home, and the only planet in our Solar System (that we know of) that actively supports life. Our planet is the third from the our Sun, orbiting it at an average distance of 150 million km (93 million miles) from the Sun, or one AU. Given the fact that Earth is where we originated, and has all the necessary prerequisites for supporting life, it should come as no surprise that it is the metric on which all others planets are judged. Earth, pictured by the crew of the Apollo 17 mission. Credit: NASA Whether it is gravity (g), distance (measured in AUs), diameter, mass, density or volume, the units are either expressed in terms of Earth’s own values (with Earth having a value of 1) or in terms of equivalencies – i.e. 0.89 times the size of Earth.

Here’s a rundown of the kinds of Diameter: 12,760 km (7,926 miles) Mass: 5.97 x 1024 kg Length of Year (Orbit): 365 days Length of day: 24 hours (more precisely, 23 hours, 56 minutes and 4 seconds.) Surface temperature: Average is about 14 C, (57 F), with ranges from -88 to 58 (min/max) C (-126 to 136 F). Earth is another terrestrial planet with an ever-changing surface, and 70 percent of the Earth’s surface is covered in oceans. Earth has one moon. Earth’s atmosphere is 78% nitrogen, 21% oxygen, and 1% various other gases. Earth is the only world known to harbor life. Find out more about Earth at a series of articles found here on Universe Today , and on this webpage from NASA. Mars: Mars is the fourth planet from the sun at a distance of about 228 million km (142 million miles) or 1.52 AU.

It is also known as “the Red Planet” because of its reddish hue, which is due to the prevalence of iron oxide on its surface. In many ways, Mars is similar to Earth, which can be seen from its similar rotational period and tilt, which in turn produce seasonal cycles that are comparable to our own. Global image of the planet Mars. Credit: NASA The same holds true for surface features. Like Earth, Mars has many familiar surface features, which include volcanoes, valleys, deserts, and polar ice caps. But beyond these, Mars and Earth have little in common. The Martian atmosphere is too thin and the planet too far from our Sun to sustain warm temperatures, which average 210 K (-63 ºC) and fluctuate considerably. Diameter: 6,787 km, (4,217 miles) Mass: 6.4171 x 1023 kg (0.107 Earths) Length of Year (Orbit): 687 Earth days. Length of day: 24 hours 37 minutes.

Surface temperature: Average is about -55 C (-67 F), with ranges of -153 to +20 °C (-225 to +70 °F) Mars is the fourth terrestrial planet in our Solar System. Its rocky surface has been altered by volcanoes, impacts, and atmospheric effects such as dust storms. Mars has a thin atmosphere made up mostly of carbon dioxide (CO2), nitrogen (N2) and argon (Ar).If you weigh 45 kg (100 pounds) on Earth, you would weigh 17 kg (38 pounds) on Mars. Mars has two small moons, Phobos and Deimos. Mars is known as the Red Planet because iron minerals in the Martian soil oxidize, or rust, causing the soil to look red. More than 40 spacecraft have been launched to Mars. You can find out more about missions to Mars here. Find out more about Mars at this series of articles on Universe Today , and at this NASA webpage. Jupiter: Jupiter is the fifth planet from the Sun, at a distance of about 778 million km (484 million miles) or 5.2 AU.

Jupiter is also the most massive planet in our Solar System, being 317 times the mass of Earth, and two and half times larger than all the other planets combined. It is a gas giant, meaning that it is primarily composed of hydrogen and helium, with swirling clouds and other trace gases. Io and Jupiter as seen by New Horizons during its 2008 flyby. (Credit: NASA/Johns Hopkins University APL/SWRI). Jupiter’s atmosphere is the most intense in the Solar System. In fact, the combination of incredibly high pressure and coriolis forces produces the most violent storms ever witnessed. Wind speeds of 100 m/s (360 km/h) are common and can reach as high as 620 km/h (385 mph). In addition, Jupiter experiences auroras that are both more intense than Earth’s, and which never stop.

Diameter: 428,400 km (88,730 miles) Mass: 1.8986 × 1027 kg (317.8 Earths) Length of Year (Orbit): 11.9 Earth years Length of day: 9.8 Earth hours Temperature: -148 C, (-234 F) Jupiter has 67 known moons, with an additional 17 moons awaiting confirmation of their discovery – for a total of 67 moons. Jupiter is almost like a mini solar system! Jupiter has a faint ring system, discovered in 1979 by the Voyager 1 mission. If you weigh 45 kg (100 pounds) on Earth, you would weigh 115 kg (253) pounds on Jupiter. Jupiter’s Great Red Spot is a gigantic storm (bigger than Earth) that has been raging for hundreds of years. However, it appears to be shrinking in recent years. Many missions have visited Jupiter and its system of moons, with the latest being the Juno mission will arrive at Jupiter in 2016. You can find out more about missions to Jupiter here.

Saturn’s relatively thin main rings are about 250,000 km (156,000 miles) in diameter. (Image: NASA/JPL-Caltech/SSI/J. Major) Saturn: Saturn is the sixth planet from the Sun at a distance of about 1.4 billion km (886 million miles) or 9.5 AU. Like Jupiter, it is a gas giant, with layers of gaseous material surrounding a solid core. Saturn is most famous and most easily recognized for its spectacular ring system, which is made of seven rings with several gaps and divisions between them. Diameter: 120,500 km (74,900 miles) Mass: 5.6836 x 1026 kg (95.159 Earths) Length of Year (Orbit): 29.5 Earth years Length of day: 10.7 Earth hours Temperature: -178 C (-288 F) Saturn’s atmosphere is made up mostly of hydrogen (H2) and helium (He).

If you weigh 45 kg (100 pounds) on Earth, you would weigh about 48 kg (107 pounds) on Saturn Saturn has 53 known moons with an additional 9 moons awaiting confirmation. Five missions have gone to Saturn. Since 2004, Cassini has been exploring Saturn, its moons and rings. You can out more about missions to Saturn here. Find out more about Saturn at this series of articles on Universe Today and at this webpage from NASA. Uranus: Uranus is the seventh planet from the sun at a distance of about 2.9 billion km (1.8 billion miles) or 19.19 AU. Though it is classified as a “gas giant”, it is often referred to as an “ice giant” as well, owing to the presence of ammonia, methane, water and hydrocarbons in ice form. The presence of methane ice is also what gives it its bluish appearance. Uranus as seen by NASA’s Voyager 2 space probe. Credit: NASA/JPL Uranus is also the coldest planet in our Solar System, making the term “ice” seem very appropriate!

What’s more, its system of moons experience a very odd seasonal cycle, owing to the fact that they orbit Neptune’s equator, and Neptune orbits with its north pole facing directly towards the Sun. This causes all of its moons to experience 42 year periods of day and night. Diameter: 51,120 km (31,763 miles) Mass: You can find out more about Uranus at this series of articles on Universe Today and this webpage from NASA . Neptune: Neptune is the eighth and farthest planet from the Sun, at a distance of about 4.5 billion km (2.8 billion miles) or 30.07 AU. Like Jupiter, Saturn and Uranus, it is technically a gas giant, though it is more properly classified as an “ice giant” with Uranus. Neptune photographed by the Voyager 2 space probe. Credit: NASA/JPL Due to its extreme distance from our Sun, Neptune cannot be seen with the naked eye, and only one mission has ever flown close enough to get detailed images of it.

Nevertheless, what we know about it indicates that it is similar in many respects to Uranus, consisting of gases, ices, methane ice (which gives its color), and has a series of moons and faint rings. Diameter: 49,530 km (30,775 miles) Mass: 1.0243 x 1026 kg (17 Earths) Length of Year (Orbit): 165 Earth years Length of day: 16 Earth hours Temperature: -214 C (-353 F) Neptune is mostly made of a very thick, very hot combination of water (H2O), ammonia (NH3), and methane (CH4) over a possible heavier, approximately Earth-sized, solid core. Neptune’s atmosphere is made up mostly of hydrogen (H2), helium (He) and methane (CH4). Neptune has 13 confirmed moons and 1 more awaiting official confirmation. Neptune has six rings. If you weigh 45 kg (100 pounds) on Earth, you would weigh 52 kg (114 pounds) on Neptune. Neptune was the first planet to be predicted to exist by using math.

Voyager 2 is the only spacecraft to have visited Neptune. You can find out more about this mission here. Find out more about Neptune at this series of articles on Universe Today and this NASA webpage. We have written many articles about the planets for Universe Today. Here are some facts about planets , and here’s an article about the names of the planets .If you’d like more info on the Solar System planets, dwarf planets, asteroids and more, check out NASA’s Solar System exploration page , and here’s a link to NASA’s Solar System Simulator .We’ve also recorded a series of episodes of Astronomy Cast about every planet in the Solar System. Start here, Episode 49: Mercury .Venus is the second planet from the Sun, and it is the hottest planet in the Solar System due to its thick, toxic atmosphere which has been described as having a “runaway greenhouse effect” on the planet. Now you know! And if you find yourself unable to remember all the planets in their proper order, just repeat the words, “My Very Educated Mother Just Served Us Noodles.” Of course, the Pie, Ham, Muffins and Eggs are optional, as are any additional courses that might be added in the coming years!

Astronomy Cast also has some cool episodes about the Solar System. Here’s Episode 68: Pluto and the Icy Outer Planets , Episode 306: Accretion Discs , and Episode 159: Planet X . The Planets of the Solar System USOE Our solar system includes many different planets. In the drawing below, click your mouse on each planet to find its name and a short bit of information about that planet. Keep in mind that the following model of the solar system shows the correct order of the planets, but the sizes of the planets or their distances from each other are not drawn to scale. Notice the order of the planets. Make sure you view information for all the planets. Which planet is closest to the sun? Which planet is the farthest away from the sun? A good way to remember the order of the planets is to memorize the following sentence. My Very Educated Mother Just Served Us Nine Pizzas. Do you get it? Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto! Now it is time for you to take The Planet Quiz. Click on your choice for the correct answer. Need a hint, or want more information?

Click on the photo of the planet to the left of the question. Photos courtesy of NASA . 1. What is the fourth planet away from the sun? 2. What planet is closest to the sun? 3. What planet is the third as you move away from the sun? 4. What planet is the farthest away from the sun? 5. What is the seventh planet as you move away from the sun? 6. What planet is the fifth as you move away from the sun? 7. What planet is the eighth as you move away from the sun? 8. What is the second planet as you move away from the sun? 9. What planet is the sixth as you go away from the sun? Check your answers by highlighting the box at the right! 1. Mars 2. Mercury 3. Earth 4. Pluto 5. Uranus 6. Jupiter 7. Neptune 8. Venus 9. Saturn Planet Facts: Interesting Facts about the Eight Planets Our solar system has eight planets: Mercury , Venus , Earth , Mars , Jupiter , Saturn , Uranus and Neptune . With the exception of Uranus and Neptune, each of these planets can be seen unaided.

All eight planets can be see through the use of an inexpensive amateur telescope or binoculars. Order of the planets Order of the eight planets from left: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune The order of planets from closest to farthest from the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. The largest planet is Jupiter, followed by Saturn, Uranus, Neptune, Earth, Venus, Mars and, the smallest planet, Mercury. If you include dwarf planets as well, the planets in order becomes Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Haumea, Makemake and Eris being the furthest from the Sun. Distance of the planets from the Sun Planet Neptune What is a planet? The answer to this question is a highly controversial one. This has not always been the case, though. In fact, before 1978 the definition of a “planet” was not really necessary. Until that time a planet simply meant a body in orbit around the Sun, that reflected sunlight, and was not a planetary moon, asteroid , or comet .

However, with the discovery of Pluto’s moon Charon in 1978 scientists were able to calculate Pluto’s mass much more accurately than ever before and soon realized that it was much smaller than they had previously believed. At a tiny fraction of the mass of Mercury , Pluto was clearly a body much smaller than any other planet. This discovery led some to question whether Pluto was actually a planet or some other type of object. In the 1990s and early 2000s the discovery of several objects in the outer solar system similar in size to Pluto made it all but necessary to come to a definitive definition of a planet. Such a definition was needed to separate those types of objects like Pluto into a distinct class, otherwise all of the newly found objects would have to be called planets as well.

In response to this uncertainty, the International Astronomical Union (IAU), the official governing body for matters concerning naming astronomical objects, came to a definition of the term “planet.” According to the IAU, a planet is a celestial body that meets the following criteria: is in orbit around the Sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and has cleared the neighbourhood around its orbit. How many planets are in the Solar System? According to the IAU’s definition for planet above, there are 8 known planets in the Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto is no longer considered a planet under the IAU definition. Are there any undiscovered planets in the solar system? There have been several additional planets hypothesized throughout history; however, none of these planets has ever been found. The most recent of these theorized planets was Planet X, a supposedly giant planet used to explain the deviations from the predicted orbits of Uranus and Neptune.

Although Planet X has never been found and scientists are still unable to satisfactorily explain the uranian and neptunian orbital discrepancies, the scientific community has almost unanimously come to the conclusion that Planet X does not exist. It is highly unlikely that there are any planets beyond the orbit of Pluto. Most Popular

Question: What is the furthest planet from the sun?
Answer: Pluto